Internal-combustion engine



J. B. MAcDONALD.

INTERNAL COMBUSTION ENGINE. APPLICATION FILED JAN. 25. 1918. RENEWEDNOV. 8, 920.

1,378,254. Patented May 17-, 1921.

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E vwemtoz 3514/ 7 If? 14%d5" J. B. MACDONALD.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED JAN. 25. I918- RENEWED NOV.B, 1920.

Patented May 17, 1921.

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J. B. MACDONALD.

INTERNAL COMBUSTION ENGINE. APPLICATION FILED JAN. 25,'19I8. RENEWEDNOV. 8, 1920.

78,254 Patented May 17, 1921.

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J. B. MACDONALD.

JNTERNAL COMBUSTION ENGINE. APPLICATION um) JAN. 25, 191B. RENEWED NOV.8. 1920.

1,378,254. Patented M 7, 1921.

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JACK B. MACDONALD, 0F OAKLAND, CALIFORNIA.

INTERNAL-COMBUSTION ENGINE.

Specification of Letters Patent.

Patented May 17, 1921.

Application filed January 25, 1918, Serial No. 213,735. Renewed November8, 1920. Serial No. 422,689.

To all whom it may concern:

Be it known. that I, JACK B. MACDONALD, citizen of the United States,residing at Oakland, in the county of Alameda and State of California,have invented certain new and useful Improvements in Internal-Combustion Engines, of which the following is a specification.

This invention is an improvement in internal combustion engines.

The principal object of the invention is the creation of a new type ofengine provided with means for scavenging or decarbonizing the cylinderor cylinders after each explosion, in order to prevent overheating,especially of airplane motors running at high speed with heavy loads.

It is the particular object of the invention to provide means forcooling the exhaust manifold of motors, because of the numerousaccidents resulting from overheated ex: haust manifolds of airplanemotors which, in some instances have melted from the intense andcontinuous'heat.

These objects are fully accomplished in the novel structure described inthe following specification and illustrated in the accompanyingdrawings, in which Figure 1 1s a vertical central section of my improvedengine showing the piston in lowest possible position. Fig. 2 is a viewsimilar to Fig. 1, but with the piston in its highest possible position.Fig. 3 is an end view of a cam and cam shaft. F i 4 is a verticalcentral section of a modi ed form of my invention showing an improvedcylinder. Fig. 5 is a vertical sectional viewv of the cam and housing,the line of section being taken parallel to the sides of the housing,and in front of the cam ring. Fi 6 is a rear elevation of the same. Fig.7 IS a bottom plan view of the cam mechanism, to show the securingscrews and the slot in the yoke. Fig. 8 is a fragmentary sectional viewof the casting 22, to show the annular portion of the valve stem and theposition of the air pipe which cools the valve. An inlet valve 50 and anexhaust valve 27 are suitably provided in the cylinder, as shown.

Referring to the drawings, 1 indicates a cylinder of an engine suitablysecured at its base to a crank-case 2. The cylinder is provided with a clinder head 3, here shown with water jac et ports 4 communicating withports 5 in the cylinder. The cylinder head is provided with a spark plug6.

for connection with an exhaust pipe.

Mounted for reciprocation within said cylinder l is a piston 7 havingrings 8 and secured to a piston rod 9 slidable through a stufiing box 10and gland 11 in the cylinder floor.

The under side of the cylinder casting is bored 'coaxially with thepiston rod and the hole tapped to receive one threaded end of acylindrical piston guide 12 extending downwardly into the crank case.

Slidable within the said cylindrical guide 12 is an auxiliary piston 13provided with piston ring 14; and secured to the piston rod 9.

The purpose of the cylinder 12 and piston 9 is to draw cold air into thesaid cylinder 12 on the explosion stroke of the plston through a pipe16, (having its intake without the cylinder,) and compress it on the upstroke of the piston within the crank case 2. p

The piston 13 is provided with a check valve 18 which is arranged toadmit air into the crank case 2 on the up stroke and close on the downstroke to draw air into cylinder 12 through pipe 16.

The end of pipe 16 is also provided with a check valve 19 arranged toadmit air on the down stroke of piston 13 and close on the up orcompression stroke of said piston.

It will be seen that by reason of this construction cold air iscompressed and is delivered to the crank case 21 during the operation ofthe engine.

The air so compressed in the crank case is delivered through a pipe 21extending through the side wall of the crank case 2 upwardly through thebottom of a casting 22 and terminating in a nozzle 23. As the speed ofthe engine increases, also will the air pressure and the amount of airbe increased in order to take care of the increase in temperature due tothe increased speed of the engine.

The casting 22 is in effect an ell, one end of which is threaded intothe upper end of the cylinder 1 as shown at 24. The opposite end of thecasting 22 is internally threadgd s cold air is blown through the nozzle23 into the exhaust pipe, it draws the burned and carbon laden gasesfrom the interior of the cylinder in the direction indicated by arrowsin Fig. 1, and into the exhaust after each ex losion.

he casting 22 is provided with a valve as shown at 32, and is pivotallyconnected at its opposite end to one end of a rod 33, the opposite endof which is secured to a yoke 34 in which is journaled a roller 36adapted which exten to traverse the perimeter of apointed cam rinlg 37secured to a shaft 38.

' he shaft 38 has acrank 39 to which is connected one end of aconnecting rod 41, the opposite end of which is suitably secured to thepiston 13.

The rod 33 is depressed, to contact roller 36 with cam 37 by anexpansion spring 42 surrounding the said rod and bearing at one endagainst the casting 22 and at the other end against a collar 43 securedto'the said rod 33. I

It results from this construction that a supply of compressed cold airis kept in the crank case 2- while the engine is running and a stream ofrelatively cold air from this supply is forced through nozzle 23 intothe exhaust drawing the carbon and refuse from the cylinders by vacuumfrom without coacting with pressure within, resulting in cleaning orscavenging the cylinder and cooling the exhaust pipe.

In the modification of my engine shown in Fig. 4, I have shown anunusual form of cylinder. The head portion of the cylinder is integralwith said cylinder and is curved to prevent accumulation of carbon. Itis also provided with a widened curve port leading to the exhaust asshownat 51. It will be seen that in this figure the casting 22 isthreaded into the exhaust port of the cylinder and secured by a bolt52.v This construction gives easy access to the interior of the cylinderfor cleaning purposes.

In Fig. 4, I haveshown a different valve control. The shaft 33 is hereshown extending from the interior of the crank case being journaledin abearing 53 secured to the side walls of the crank case by bolts 54.

The rod 33 extends through a stufling box 56 and through the base ofcasting 22 and,

when driven by cam 37, raises one end of a rocker arm 57, one end ofwhich is provided with a hole to receive the end of said rod and bearsagainst a nut 58 threaded on the rod 33.

The rocker arm 57 is pivoted on a bolt 61 near its center, and theopposite end of the said arm is rovided with a hole through d thereduced threaded end of a valve stem ;62 attached to valve 27. As ameans of adjustment a wing nut 63 is threaded onthe end of valve stem62.

The valve 27 is normally held in closed position by a coiled expansionspring 59 one end of which bears against a pin 64 through the valve stem62 and the opposite end bears against casting 22.

The cold air is conducted as in the previous figures through pipe 21 andnozzle 23 into the exhaust pipe. This cools the exhaust pipe as well ashaving a somewhat cooling influence on the cylinder.

The valve stem 62 has an annular reduced portion 66 thereon, and thepipe 21 has a branch passage 67 terminating in front of the'reducedportion 66, Fig. 7. In the normal closed position of the valve 27, airpasses through the passage 67 to blow onto the valve stem and also onthe rear face of the valve, as can be clearly seen, this cooling thevalve and the adjacent parts.

The valve upon being opened by the action of the cam 36, its stem movesforward and causes the pipe 67 to be closed. This allows all of the alrto pass out through the nozzle 23. The valve is actuated by means of apointed cam ring 37, which traverses the perimeter of the yoke '34. Uponcoming slot 73 cut into the rear face of the yoke 34 acts as a guide forthe cam and prevents any side movement.

What I claim asnew and wish to cover by Letters Patent is:

' 1. An internal combustion engine comprising a crank shaft, aconnecting rod, a

piston rod provided with a piston reciprocable within an upper cylinderand the .said piston rod also provided with an auxiliarypistonreciprocable within an auxiliary cylinder secured to the nethersurface of said upper cylinder, the said upper cylinder secured to anair tight crank case, the said auxiliary cylinder provided with an airintake pipe leading to the exterior of the crank case and provided witha check valve arranged to allow ingress and prevent egress of air, thesaid auxiliary piston provided with a check valve to permit ingress ofair into said crank case on the up stroke of the said piston and toprevent ingress of air and allow compression of air in the crank caseduring the down stroke of said auxiliary piston, the said crank caseprovided with a discharge pipe leading to and discharging within a valvecasting suitably connected at one end with an exhaust pipe and suitablyconnected at the other end with the said upper cylinder near the top ofsaid upper cylinder, the said casting provided with a valve adapted whenr'eciprocated to open and close a port in said casting leading to theinterior of said upper cylinder, said valve provided with a coiledexpansion spring adapted to normally close said valve by pressing at oneend against the said casting and at the opposite end against a pin inthe stem of said valve.

2. An internal combustion engine comprising a crank shaft, a connectingrod, a piston rod provided with a piston reciprocable within an uppercylinder and the said piston rod also provided with an auxiliary pistonrecip-rocable Within an auxiliary cylinder secured to the nether surfaceof said upper cylinder, the said upper cylinder se cured to .an airtight crank case, the said auxiliary cylinder provided with an airintake pipe leading to the exterior of the crank case and provided witha check valvearranged to allow ingress and prevent egress of air, thesaid auxiliary piston provided with acheck valve to permit ingress ofair into said crank case on the up stroke of the said piston and toprevent ingress of air and allow compression of air in the crank caseduring the down stroke of said auxiliary piston, the said crank caseprovided with a discharge pipe leading to and discharging within a pipeof the engine suitably connected at one end with an exhaust pipe.

3. In an internal combustion engine, the combination with the exhaustpipe and exhaust valve thereof, of means actuated by the'engine forsupplying cold air during the operation of the engine, a connection fromsaid means fordirecting streams of 'air from said supply into the pipe,a passage from 'said connection for directing streams of air from saidsupply upon the valve, said passage being controlled by the position ofthe valve.

In testimony whereof I ailix my signature.

JACK B. MACDONALD.

